Blasting cartridge and apparatus for charging the same



Dec. 26, 1933. F. H. ARMSTRONG BLASTING CARTRIDGE AND APPARATUS FOR CHARGING THE SAME Filed May 31. 1930 5 Sheets-Sheet l Dec. 26, 1933. F. H. ARMSTRONG BLASTING CARTRIDGE AND APPARATUS FOR CHARGING THE SAME Filed May 31, 1930 5 Sheets-Sheet 2 [7W6 7LEW Dec. 26, 1933. F. H. ,ARMSTRONG BLASTING CARTRIDGE AND APPARATUS FOR CHARGING THE SAME Filed May 31. 1930 5 Sheets-Sheet .lllllllll I720 eiatoi Dec. 26, 1933. F. H. ARMSTRONG BLASTING CARTRIDGE AND APPARATUS FOR CHARGING THE SAME Filed May 31, 1930 5 Sheets-Sheet 4 Dec. 26, 1933. F. H. ARMSTRONG 1,941,196

BLASTING CARTRIDGE AND APPARATUS FOR CHARGING THE SAME Filed May 31, 1930 5 Sheets-Sheet 5 [4527295666 1 Ew n/Z57 wgwm W w,

Patented Dec. 26, 1933 UNITED STATES BLASTING CARTRIDGE AND APPARATUS FOR CHARGING. THE SAME Frank 1!. Armstrong, Chicago, Ill., assignor to Safety Mining Company, Chicago, 111., a corporation Application May 31, 1930. Serial No.458,566

16 Claims.

This invention relates to blasting cartridges of the indestructible and rechargeable type designed for use of a compressed gas as the blasting medium.

A The primary object of the invention is to provide a simplified cartridge, less expensive to produce and maintain, more efiicient in handling and performance and better adapted to existing conditions in mines and other places of use.

One of the more important characteristics of the-improved cartridge, which may be stated as an object of the invention, is an entirely new method of introducing the blasting medium into the cartridge. This method of charging is in a large measure responsible for the extreme simplicity of the cartridge.

It is also an object of the invention to provide asimple and eflicient charging device for carrying out the new method of charging the improved cartridge.

Other objects of the invention are concerned with particular features of construction, assembly, and operation, all of which are clearly disclosed in the following description and the accompanying drawings.

Figure 1 is an assembly view in side elevation showing the charging device with a cartridge positioned therein preparatory to charging.

Figure 2 is a top plan view of the device shown in Figure 1.

Figure 3 is a view in vertical section taken on line 3--3 of Figure 1 and showing the improved cartridge, partly in section, in position corresponding to one of the steps of the charging operation.

Figure 4 is a view in vertical section showing the upper portion of the charging device and associated therewith a portion of a cartridge, also in vertical section, and with the parts relatively positioned in accordance with another step in the charging operation.

Figure 5 is a view similar to Figure 4 but showing the parts positioned according to another step of the charging operation.

Figure 6 is a sectional plan view taken on line 66 of Figure 3.

Figure 7 is a sectional detail view taken on line 7-7 of Figure 1.

Figure 8 is a detail view in vertical section showing a portion of the lifting plunger and its cylinder.

Figure 9 is a detail view in vertical section showing the hydraulic motor for operating the lifting plunger.

Figures 10 and 11 are vertical sectional views on an enlarged scale showing the upper portion of the cartridge and with the associated charging nozzle shown in dotted outline. The positions of the parts in these views correspond to Figures 4 and 5 respectively, which depict two difierent steps in .the charging operation.

Figure 12 is a view in longitudinal section showing the construction and design of a complete cartridge body. v

Figure 13 is an end elevation of the charging end of the cartridge.

Figure 141s a transverse sectional view taken on line 14-14 of Figure 11 and showing particularly the loop formed in the end of one of the squib leads and disposed in the center of the plug in the heater unit to provide contact with the electrode.

Figure 15 is a view in longitudinal section showing the discharge cap and rupturable disc associated with one end of the cartridge body.

Figures 16 and 17 are views in longitudinal section showing two modifications of the supporting arrangement for the heater unit.

Owing to the mutually dependent relation between the cartridge and the method and apparatus for charging the same, it is necessary that, to a large extent, they be jointly considered. However, in the interest of clearness, the cartridge construction and design will first be separately described.

The cartridge is completely illustrated in Figures 10 to 15 inclusive. Figure 12 shows the complete body portion 1, of the cartridge and from this view it will be noted that the body consists merely of a section of seamless steel tubing suitably formed at its opposite ends to receive the two end assemblies. The section of tubing from which the body is made is originally of substantially uniform internal and external diameters throughout its length. The tube is first up-set for a short distance at each end to increase the wall thickness and provide an internal diameter slightly less than that of the bore 2. The forging is then bored out at each end to the diameters indicated at 2 and 3 respectively, after which screw threads are formed in the bores 3 as indicated at 4. It is noted that the body is of extremely simple construction and involves a minimum of forging work. It is also noted that the opposite ends of the body are of identical construction, thus permitting standardization of parts and rapid production.

The discharge assembly shown in Figure 15 is generally similar to previous designs but differs therefrom in certain very important respects. 110

Heretofore it has been necessary to employ a separate shear ring in conjunction with the discharge cap and rupturable disc 6 to secure sat isfactory results. This shear ring is an annular element formed of hardened steel and is positioned between the rupturable disc and the ad- Jacent end of the discharge cap to provide a durable shearing edge for the disc. The internal diameter of the shear ring is sufllciently smaller than that of the discharge cap to permit free passage of the sheared slug into and from the bore of the cap. Without such a special shear ring it has heretofore been very diflicult and in many instances practically impossible to remove the sheared slug from the cap. According to the present invention the shear ring is omitted and the discharge cap made to serve its purpose. The discharge cap is threaded into the cartridge body until its end engages and exerts pressure on the rupturable disc. The discharge cap may be 10- cally treated to harden the shearing surface, or the entire cap may be formed of a material suffi- .ciently hard for this purpose. This arrangement would not be feasible were it not for the special provision made to insure easy removal of the sheared slug. This provision consists in forming a substantially conical pocket or depression 7 at the end of the bore in the cap. The force of discharge of the cartridge causes the sheared slug to conform to the contour of the pocket, thus reducing its diameter to such an extent that it will fall freely thru the bore of the cap. The pocket is so designed, however, that the deformed slug cannot pass thru the radial discharge ports of the cap. The particular contour of the slug deforming surface herein shown has been found to be very efiicient, but it should be apparent that many other forms may be employed with the same final result.

The construction of the opposite end of the cartridge will now be described, with particular reference to Figures 10 and 11. The parts associated with this end of the cartridge are concerned chiefly with the charging of the cartridge and, for convenience, will be hereinafter referred to collectively as the charging assembly. The shell top 8 of this assembly is screw threaded into the end of the cartridge body in the same manner as the discharge cap and has an external portion of the same diameter as the cartridge body. A suitable gasket 9, preferably copper, is interposed between the end of the shell top and the opposed surface in the cartridge body to effect a gas tight seat at this point. The sealing surface on the shell top is relieved by an annular groove 10 to improve the sealing effect.

Cartridges of this type usually employ a heater unit designed to be electrically energized and to liberate the amount of heat required to increase the pressure of the gas charge toa predetermined point. In the instant case, such a unit is shown as consisting of a paper tube 11 designed to be filled with a suitable amount of an ignitible heat producing chemical compound. One end of the tube may be closed by a paper cap (not shown), while the other end is closed by a plug 12, preferably made of wood, and having a flanged head which extends beyond the circumference of the tube. The plug 12 is secured in the-end of the tube with glue or other suitable means. In the center of the plug is a small passage 13 which terminates in the center of a conical depression 14 in the outer end thereof. One lead of an electric squib or match head" 15 extends through passage 13 and terminates in a loop or similar form of contact in the center of the conical depression 14. The position of the heater unitis determined and maintained by a heater support 16 which is screw threaded into the lower end of the shell top and whose interior is of a two diameters, the smaller of which conforms to the diameter of the tube 11 with sufllcient clearance to permit' passage of the tube through the heater support, the end opposite plug 12 being inserted first, but insufficient to permit pasi sage of plug 12. A light coil spring 1'7 surrounds the upper end of the heater unit and is interposed between the flange on plug 12 and the shoulder in the heater support, thus constantly forcing the heater unit and its plug 12 outwardly 1 of the cartridge. The inner end of the heater support is provided with tool receiving slots 18 to facilitate insertion and removal of the support. The shell top is provided with a cylindrical screw threaded pocket 19 having a tapered ap- 1 proach to a second or bottom pocket 20, the walls of the latter being also slightly tapered. A central axial passage of small diameter extends from the bottom pocket through to the interior of the shell top. The bottom pocket is designed to re- 1 ceive the hard fibre washer 22 which, in conjunction with the flanged electrode 23 serve to seal the passage 21. The electrode is preferably of integral construction and the shank and flange thereof are joined by a fillet which serves to 1 compress the adjacent circular edge of the fibre gasket and cause it to closely and tightly conform to the pocket. The gasket is, of course, an insulator and thus keeps the electrode out of electrical contact with the shell top. The shank of 1] the electrode passes freely thru and out of contact with the wall of hole 21 and its conical end engages the squib contact in the center of the conical depression in plug 12. It is to be noted that the spring 17 is normally under compression 1] and that in addition to maintaining contact between the plug and the shank of the electrode, it constantly urges the electrode in an axial direction for a purpose to be presently explained.

The threaded pocket 19 in the shell top is provided with a nut 24 which is designed to exert pressure on the electrode 23 to seal it upon its fibre seat 22. This nut is provided with a central opening which telescopes over an extension 25 on the electrode. An insulating washer 26 is interposed between the lower surface of the nut and the adjacent surface of the electrode flange and likewise, an insulating sleeve 27 is positioned between the extension 25 of the electrode and the wall of the opening in the nut. Thus, it is apparent that the electrode is completely insulated from the remainder of the cartridge and that it has electrical contact only with the squib lead which extends through plug 12. It is also apparent that the electrode is accessible through the open end of bushing 27 for the purpose of connecting a source of electricity thereto. In this connection it is noted that the other lead of squib 15 passes out of the heater unit between plug 12 and tube 11 where its and lies beneath and in contact with spring 17, which in turn is in electrical connection with the shell top through the medium of heater support 16. Therefore, the squib 15 of heater unit 11 is included in an electrical circuit, the terminals of which are the electrode 23 and shell top 8. The extension 25 of the electrode is provided with a bore 23 to receive any suitable form of terminal or connector, while the other connection may be made through holes 29 in the shell top. In order I J to prevent accidental contact with the electrode and also to exclude foreign matter, .there is provided a cover plate 30 pivoted to the nut 24 by means of a rivet or the like 31.

The foregoing is a practically complete description of the improved cartridge insofar as its construction is concerned and yet, it will be noted, nothing has been said as to the method or means for introducing a charge of compressed or liquefied gas into the cartridge. The fact is that this operation does not require separate and distinct means as has heretofore been the case, but is an additional function of the structure already described. Still referring to Figures 10 and 11, the surface 32 of the shell top immediately surrounding the electrode nut 24 is adapted to receive a sealing gasket 33 on which may be seated a charging nozzle 34, shown in dotted outline. Disposed within the nozzle is a wrench 35 having on its lower surface a plurality of pins, preferably four, adapted to engage in corresponding sockets 36 formed in the nut, the latter being more clearly shown in Figure 13. Referring particularly to Figure 11, it will be noted that when the nut is screwed outwardly, the spring 1'7 acting through plug 12 causes the electrode to follow, thus lifting the flanged portion of the electrode from its seat on sealing washer 22. With the parts in this position the outer end of passage 36 formed in the nut is beyond the threads in the shell top and open to the interior of the nozzle, thus permitting gas to flow through passage 36, around electrode 23 and through passage 21 into the cartridge. In order to facilitate passage of the gas around the heater support to the interior of the cartridge body, apertures 3'7, 38 and 39 are formed in the heater support, apertures 37 and 38 serving to by-pass the flange on the plug and apertures 38 and 39 serving to by-pass the threaded connection between the heater support and shell top. After the desired charge has been introduced into the cartridge, the wrench 35 may be operated to screw the nut inwardly, thus reseating the electrode and preventing the escape of gas from the cartridge. The inward movement of the nut also carries the end of passage 36 into the threads of the shell top, thus sealing the same against the entrance of dirt. After charging, the nozzle 34 and sealing gasket 33 may be removed and the cartridge is then ready for use. The purpose of the rib or flange 40 is merely to protect the sealing surface 32 and serve as a guide for the nozzle. The pipe 41 leading into the nozzle is intended for connection to a supply of gas or other medium and there is ample clearance within the nozzle around the wrench to permit the gas to pass into the cartridge.

The blasting medium commonly employed in cartridges of this type is highly compressed or liquefied carbon dioxide and the pressure at which this medium is charged into the cartridges is close to 1,000 pounds per square inch. In dealing with pressures of this order, it is quite apparent that not only must the cartridge be of correct design and sturdy construction, but also that the mechanism employed for charging be quite sturdy. In fact, it has been found quite dimcult to conveniently provide the force necessary to hold the charging nozzle in sealing engagement with the shell top during charging. However, there is disclosed in the attached drawings a mechanism for this purpose which is very satisfactory and yet not of a complicated or costly nature.

The method of charging the improved cartridge is generally described above, but will be more particularly described in connection with the charg plunger is operated in part by a hand lever 4'7 secured to a rock shaft 48 journaled on the rear face of the channel, the rock shaft being in turn connected to the plunger by a pair of crank arms 49, one disposed at each side of the channel, and links 50 pivotally connected to the crank arms and plunger. The bolts 51 which connect links 50 to plunger 45 operate in vertical slots 52 formed in the sides of the channel. The function of the hand lever and its operating connections just described is to move the plunger upwardly until the cartridge carried thereby comes into engagement with the charging nozzle carried by the top plate 43, the pressure required to effectively seal the nozzle on the shell top being provided by separate means to be presently described. The charging device is so proportioned with reference to the size of cartridge to be charged that the shell top comes into engagement with the nozzle before the pins or bolts 51 have reached the upper ends of slots 52, thus providing for additional upward travel of the plunger, which is utilized by the separate pressure device.

Referring now to Figures 1, 2 and 9, there is provided a casting 53 having an ofl or other fluid reservoir 54, a cylinder 55 and a cap 56 which serves both to retain the fluid and as a guide for the rod 5'7 of plunger 58. Ports 59 are arranged to permit the flow of fluid from the reservoir into the cylinder when the plunger 58 is at the upward limit of its travel. This pump assembly is bolted to one side of the channel member as shown in Figures 1 and 2. A pipe 60 connects the lower end of cylinder 55 with the lower end of cylinder 44. The operating connections for plunger 58 include a foot pedal 61 pivoted at the back of the channel member, a connecting rod 62, a pivoted cross lever 63 carried by the upper end of plunger rod 5'7, and an anchor link 64. A

From the description thus far, it will be understood that the movement of a cartridge to be charged into sealing engagement with the charging nozzle is effected in two stages, first, by

means of the hand lever moving the cartridge upwardly till the shell top engages the nozzle, thus taking up practically all of the travel of the cartridge but without the application of any considerable amount of power thereto, and second, by means of the foot operated hydraulic device exerting a high pressure on the cartridge but without effecting any great amount of travel thereof. 01' course, both the travel and pressure requirements could be fulfilled by the hydraulic device, but this would require an excessively long stroke of the hydraulic plunger which cannot be conveniently arranged.

From Figures 3, 4, and 5 it will be noted that nozzle 34 has a parti-spherical top surface which fits and cooperates with a similarly formed surface' on the plate 43. A ring 68 adjustably suspended Irom plate 43 engages a flange on the upper end of the nozzle and serves to hold the latter in proper position. In adjusting the ring 68, suflicient clearance is provided to permit slight universal movement of the nozzle in order that it may readily accommodate itself to the sealing surface on the shell top.

The shank of wrench 35 extends thru a stutfing box 69' in the nozzle and upwardly thru a central opening in plate 43. The upper end of the wrench shank is squared to fit a socket in ratchet wrench '70. The normal position of the pin wrench 35 and its associated ratchet wrench '70 is shown in Figure 3, from which it will be noted that the head of pin wrench 35 extends slightly below the lower surface or nozzle 34, while the head of wrench '70 lies in engagement with the upper surface of plate 43. This normal position of the parts is maintained by a compression spring 71 which is confined between plates '72 and '73, the former being adjustably positioned on bolts '74 and the latter having hearing on wrench '70 through the medium of a ball thrust bearing '75. In this connection, it is noted that the thrust of the spring is imparted to pin wrench 35 due to the engagement of wrench '70 with the shoulder formed on the shank of pin wrench 35 adjacent the squared end thereof. Since the function of wrench 35 is to screw the electrode nut 24 downwardly to seal the electrode 24, it should be understood that the principle function of spring '71 is to cause wrench 35 to follow the electrode nut in its downward movement. It will be understood, of course, that this prevents the imposition of severe strains on the pins of wrench 35, such as would occur if separation of the electrode nut and wrench head were permitted.

The operating sequence as regards charging is shown in Figures 5, 4, and 3, respectively. Ordinarily, the electrode nut 24 is adjusted to the position shown in Figures 5 and 11 before the cartridge is placed in the charging device, although this would not be necessary if wrench 70 were of the reversible ratchet type. In Figure 5 a cartridge is shown in charging position in the charging device, with its parts positioned to admit carbon dioxide or other gas into the same. Figure 4 shows the position of the cartridge and charging device after a charge has been introduced into the cartridge and the electrode nut 24 screwed downwardly by ratchet wrench '70 and pin wrench 35 to seal electrode 23. In Figure 3, the dotted line position shows the cartridge after the hydraulic pressure on plunger 45 has been relieved, but before the cartridge has been lowered by the hand lever 47. In the full line position (Figure 3) the cartridge is completely lowered and ready for removal from the charging dev ce.

Figures 16 and 1'7 show two slightly modified forms of cartridge wherein the heater support is omitted. According to Figure 16, the spring 1'7 has its seat on a shoulder '76 formed in the cartridge body, thus obviating the necessity for a separate heater supporting element. In Figure 17 there is provided a ring member '77 which serves both as a gasket and a seat for the spring. Apertures '78 are provided to permit passage of the gas into the cartridge. Otherwise, the cartridges of Figures 16 and 1'7 are similar to that above described.

What I claim is:

1 A blasting cartridge comprising a metallic body having a gas chamber formed therein. a pressure responsive discharge device on said body, a charging opening in said body, a member positioned adjacent said opening and serving as a valve to either permit the introduction of gas 81 into said chamber thru said opening or completely seal said opening against the escape oi. gas from said chamber, said member being completely insulated from said body and being accessible both to the interior and exterior of said body, 81 whereby it is adapted to serve as an electrode for conducting an energizing current of electricity from the exterior to the interior of said cartridge.

2. A blasting cartridge comprising a metallic body having a gas chamber formed therein, a 91 pressure responsive device on said body, a charging opening in said body, a member positioned adjacent said opening and serving as a valve to either permit the introduction of gas into said chamber thru said opening or completely seal said 91 opening against the escape of gas from said chamber, means for exerting pressure on said member to seal said opening and means for moving said member from sealing position when the first said means is moved to relieve the pressure. 101

3. A blasting cartridge comprising a metallic body having a gas chamber formed therein, a pressure responsive discharge device on said body,

a charging opening in said body, a member positioned in said body adjacent said opening and 101 having a part extending through said opening into said chamber, means for completely insulating said member from said body, said member serving to seal said opening when in one position and to permit the introduction of gas there- Ill thru when in another position, and means for moving said member to its respective positions.

4. A blasting cartridge comprising a metallic body having a gas chamber formed therein, means on said body for venting said chamber upon the Ill attainment of a predetermined pressure therein,

a charging opening in said body having communication with said chamber, a movable valve member for said opening having a portion extending into said chamber, said member being 12( insulated from said body and being accessible to the exterior of said body, whereby it is adapted to serve as an electrode.

5. A blasting cartridge having a gas chamber and embodying an electrode extending into said 12 chamber but completely insulated from said cartridge, said electrode being movable and adapted to serve as a valve to permit the introduction of gas into said chamber.

6. A blasting cartridge embodying an operating part exposed to the exterior thereof," and a nozzle seat surrounding said part, in combination with a charging nozzle adapted to engage said seat and having therein an operating member designed i'or cooperation with said operating part, and means for operating said operating part from the exterior of said nozzle.

'7. A blasting cartridge embodying an electrode movable to and from sealing position and a member operable to effect sealing movement of said electrode, in combination with a nozzle adapted to surround said member and having sealing engagement with said cartridge, said nozzle embodying means for operating said member while said sealing engagement is maintained.

8. A blasting cartridge embodying an electrode adapted to be moved to and from sealing position, means for positively moving said electrode toward sealing position and yieldable means constantly urging said electrode from sealing position.

9. A discharge cap for blasting cartridges comprising a body having an axial bore open at one end and at its other end terminating in a concave,

slug deforming surface, for the purpose described, and a substantially transverse discharge port leading from said bore to the exterior of said body.

10. A discharge cap adapted to be associated with a blasting cartridge, said cap having an axial bore of substantially uniform diameter open at one end and at its other end terminating in a substantially conical, slug deforming surface, for the purpose described, and a substantially transverse discharge port leading from said bore to the exterior of said body.

11. A blasting cartridge comprising a cylindrical hollow body having a shoulder formed adjacent an open end thereof and threads formed internally of said body outwardly of said shoulder, a rupturable disc positioned on said shoulder, a discharge cap having an externally threaded shank adapted to engage the internal threads of said body and to have its end engage said disc and hold same in engagement with said shoulder, said cap having an axial bore opening at the end adjacent said disc and terminating at its opposite end in a substantially concave surface, and a discharge port extending transversely from said bore to the exterior of said cap.

12. In a mechanism of the character described, a blasting cartridge embodying an electrode movable to and from sealing position and a member operable to effect sealing movement of said electrode, in combination with a nozzle adapted to surround said member and having sealing engagement with said cartridge, said nozzle embodying means movable with respect thereto for operating said member while said sealing engagement is maintained.

13. In a mechanism of the character described, a blasting cartridge embodying an operating part exposed to the exterior thereof, and a nozzle seat surrounding said part, in combination with a charging nozzle adapted to engage said seat and having therein an operating member movable with respect to said nozzle and designed for cooperation with said operating part, and means for operating said operating part from the exterior of said nozzle.

14. In a mechanism of the character described, a blasting cartridge embodying an operating part exposed to the exterior thereof, and a nozzle seat surrounding said part, in combination with a charging nozzle adapted to engage said seat and having therein an operating member in gas tight relation to and movable with respect to said nozzle and designed for cooperation with said operating part, and means for operating said operating part from the exterior of said nozzle.

15. A blasting cartridge comprising a cylindrical hollow body having an integral shoulder formed adjacent an open end thereof and threads formed internally of said body outwardly of said shoulder, a rupturable disc positioned on said shoulder, and a discharge cap having an externally threaded shank engaging the internal threads of said body and directly engaging said disc for holding the latter in engagement with said shoulder.

16. A discharge cap adapted to be associated with a blasting cartridge, said cap having an axial bore of substantially uniform diameter open at one end, a shearing edge of substantially the same diameter as said bore associated with said open end, means at the remaining end of said bore to deform a slug, cut by said edge, to reduce its diameter below that of the said bore, and a discharge port leading from said bore to the exterior of said body.

FRANK H. ARMSTRONG. 

